The Inter-Relations of Hydrogen and Deuterium Molecules

It has been shown that neither stopcock grease nor water in a Pyrex or soft-glass vessel affect the concentration of hydrogen-deuterium mixtures. Diffusion through palladium gives a concentration of the isotopes which is about that to be expected from an atomic diffusion process. Desorption from charcoal at liquid air temperatures gives the concentration effect to be-expected from a diffusion as molecules. Mercury, Pyrex and soft-glass surfaces at room temperature and charcoal at liquid air temperatures do not promote the reaction between hydrogen and deuterium. Chromium oxide and nickel-kieselguhr surfaces promote the reaction between hydrogen and deuterium in the temperature range between -190 degrees and 110 degrees C. A palladium surface catalyzes the reaction at 270 degrees C. Experimental values have been obtained for the equilibrium constant of the reaction between hydrogen and deuterium from the temperature of liquid air upwards, in accord with theoretical calculations by Urey and Rittenberg based on statistical mechanics.